Hi, I am looking to implement a system to use as a prepaid service. I am aware that asterisk could do this with app_prepaid. However I am not sure if this is the best solution. Does anyone know if SER has a simmillar solution. Would I be right in assuming that SER as a SIP server is more scalable and can handle with more registerations/users ? Alternatively would it be a good idea to use SER as the SIP server and use asterisks as the PSTN gateway amd to manage the prepaid billing (given that only off net calls will be considered chargeable) Your commments and feedback will be greatly appreciated. Umar Sear